1. Field of the Invention
The present invention relates to a digital broadcast receiving apparatus for receiving a digital broadcast signal and outputting an analog video signal and an analog audio signal and in particular to a digital broadcast receiving apparatus for multiplexing a closed caption provided from a digital broadcast signal in a video signal and outputting the multiplexed signal.
2. Description of the Related Art
A digital broadcast receiving apparatus in a related art receives a digital broadcast signal of a selected channel, converts the digital broadcast signal into an analog video signal and an analog audio signal, and outputs the analog video signal and the analog audio signal to an analog display such as a television receiver. When an analog broadcast closed caption is contained in the digital broadcast signal, in converting the received digital broadcast signal into analog form, a closed caption signal for analog broadcast (an analog broadcast closed caption signal) is extracted.
Inserting the analog broadcast closed caption signal in the 21st scanning line (LINE 21) of a video signal is standardized in EIA (Electronic Industries Association)-608, and up to four closed captions 1 to 4 (CC1 to CC4) can be broadcast. Thus, the extracted closed caption signal is inserted in LINE 21 of a video signal and the multiplexed video signal is output to the display. Based on the video signal, the display displays program video on a screen and also displays a closed caption of a text broadcast on the screen, as shown in FIG. 5. FIG. 5 is a schematic drawing to show a state in which program video and the closed caption are displayed on the screen of the display. Program video is displayed on the whole of a display screen 100 of a display 30 and a closed caption 101 is displayed in a predetermined range near the lower end of the display screen 100 so that it is superposed on the program video.
The digital broadcast receiving apparatus has a function of outputting a menu image to the display so that the user can change the setup description of the apparatus main unit and easily visually check the setup description. The menu image is stored in memory and when the viewer performs setting change operation, the menu image is superposed on a video signal for output. The display displays the video signal containing the menu image on the screen, whereby a setting change menu screen as shown in FIG. 6 is displayed. FIG. 6 is a schematic drawing to show a state in which program video and the menu screen are displayed on the screen of the display. Program video is displayed on the whole display screen 100 of the display 30 and a menu screen 102 is displayed in a predetermined width from the center of the display screen 100 to the upper and lower ends thereof so that it is superposed on the program video.
In the digital broadcast receiving apparatus in the related art, however, if a closed caption signal is inserted into the video signal containing a menu image, the closed caption 101 and the menu screen 102 may overlap each other on the screen 100 of the display 30 as shown in FIG. 7 (overlap portion 110 in the figure). If the closed caption 101 and the menu screen 102 overlap each other, it becomes hard for the viewer to see the menu screen 102 and the closed caption 101.
Hitherto, various arts for the digital broadcast receiving apparatus have been proposed including those disclosed in Japanese unexamined patent publications JP-A-9-107529 and JP-A-2001-326870. However, a method of solving the problem described above is not disclosed in neither of the publications.